ARVOR (Profiling Floats)

This utility converts in-situ profiling float (T/S profile) ASCII files into a DART observation sequence (obs_seq) file.

Overview

Profiling floats such as ARVOR-C and ARVOR-I (ice-capable) record seawater temperature and salinity at multiple depths during dives and ascents. This converter ingests ASCII (.csv format) files of these profiles and writes them into a DART obs_seq format for assimilation with DART. The csv files are expected to have on the first line a header with different fields names followed by data entries.

The converter reads the following from the raw data:

  • dat – timestamp

  • lat – latitude in degrees

  • lon – longitude in degrees

  • pres – pressure in dbar converted to depth in meters

  • sea_water_temperature – temperature in Kelvin, converted to C.

  • salinity – salinity in psu

Note

Time handling: The converter reads the dat column, parses the timestamp, and constructs a DART time_type using the Gregorian calendar. The expected time format is YYYY-MM-DDThh:mm:ssZ

Build & Run

Build as usual with DART converters. Then run, ./arvor_to_hf, with an input.nml that includes a namelist section that looks like:

&arvor_to_obs_nml
   file_in           = 'ARVOR_20251006_300534063313500.csv',
   file_list         = '',               ! path to list of files (or '')
   file_out          = 'obs_seq.arvor',
   obs_error_temp    = 0.02,             ! temperature error standard deviation (C)
   obs_error_sal     = 0.02,             ! salinity error standard deviation (PSU)
   avg_obs_per_file  = 500000,           ! pre-allocation limit
   debug             = .true.
   /

  • Exactly one of file_in or file_list must be non-empty.

  • Temperature values in the raw file are in Kelvin and are converted to degrees Celsius.

  • Pressure values (dbar) are converted to depth in meters (+ down).

  • Any missing values or bad rows (lat, lon, pres, temp, or saln = missing) are skipped.

  • Observation kinds: FLOAT_TEMPERATURE and FLOAT_SALINITY.

Namelist Summary

Namelist item

Type

Default / Allowed values

Description

file_in

character(len=256)

'' (empty)

Path to single ASCII profile file.

file_list

character(len=256)

'' (empty)

Text file listing profile files.

file_out

character(len=256)

'obs_seq.arvor'

Output obs_seq file name.

obs_error_temp

real(r8)

0.02

Standard deviation error for temperature.

obs_error_sal

real(r8)

0.02

Standard deviation error for salinity.

avg_obs_per_file

integer

500000

Estimate of valid obs per file. Used for pre-allocation. Number of files times this number must be larger than the total number of output observations.

debug

logical

.true.

If true, prints detailed conversion log.

Output

A new observation sequence file named according to file_out. Each observation record includes location (lat, lon, depth), time, and one of the two kinds (temperature or salinity), with error variance set to the square of obs_error_temp or obs_error_sal.

If debug = .true., a summary will be printed (similar to the one below):

Input file: #2 T_HCSV00_C_BMKG_20251006061000_ARVORC_300534063012970.csv
  >> Total number of obs: 25
  >> Valid observations count: 24
     * obs #  1, lat: -5.7368, lon: 113.8890, dep: 65.0270, T: 28.6840, S: 33.9690, date: 2025 Oct 06 06:10:00
     * obs #  2, lat: -5.7368, lon: 113.8890, dep: 62.2036, T: 28.6840, S: 33.9680, date: 2025 Oct 06 06:11:05
     * obs #  3, lat: -5.7368, lon: 113.8890, dep: 59.3703, T: 28.6840, S: 33.9680, date: 2025 Oct 06 06:12:10
     * obs #  4, lat: -5.7368, lon: 113.8890, dep: 56.5468, T: 28.6840, S: 33.9680, date: 2025 Oct 06 06:13:15
     * obs #  5, lat: -5.7368, lon: 113.8890, dep: 53.7233, T: 28.6840, S: 33.9680, date: 2025 Oct 06 06:14:20
     * obs #  6, lat: -5.7368, lon: 113.8890, dep: 50.8898, T: 28.6840, S: 33.9680, date: 2025 Oct 06 06:15:25
     * obs #  7, lat: -5.7368, lon: 113.8890, dep: 48.0663, T: 28.6840, S: 33.9680, date: 2025 Oct 06 06:16:30
     ...

> Ready to write 286 observations:
  write_obs_seq  opening formatted observation sequence file "obs_seq.arvor"
  write_obs_seq  closed observation sequence file "obs_seq.arvor"
  arvor_to_obs Finished successfully.

Further reading

For background on the observing platform supported by this converter:

  • Argo Program: “Float types” – Official overview of the various Argo float families, including ARVOR, PROVOR, and DEEP-Arvor.

  • Le Reste et al. (2016): “Deep-Arvor: A new profiling float to extend the Argo observations to 4000 m” – Detailed design and performance study of the deep variant of the ARVOR float.

  • NKE Instrumentation: “Profiling floats” – Manufacturer specifications for the ARVOR and PROVOR families (pressure range, sensors, telemetry).